TAMPA, Fla. — This was more than a season ending. This was an era coming to close, and the disappointment was tenfold.

The Islanders lost, 4-0, to the Lightning in Game 5 of their second-round playoff series on Sunday afternoon at Amalie Arena, and it brought on the summer of total uncertainty that begins now. With so many necessary personnel decisions, with new ownership taking over, and now with a small taste of postseason success, who and what the Islanders are going to be in training camp come September is the question coloring this overwhelming letdown.

“It’s obviously really hard to win the Stanley Cup,” said captain John Tavares, who had a disappointing series, no points after Game 1, after being such an unstoppable force in the opening-round victory over the Panthers — the franchise’s first series win since 1993.

“Each and every round is so different. Different teams, different styles, ups and downs of the series, just how much tougher it gets as you move along. We just weren’t good enough at some crucial times in this series. We didn’t take advantage of being at home.

“I’ll take a lot of responsibility for that. I’m being counted on for a lot, so you just try to learn from where you need to be better and the differences in the series and how we can overcome it and become a better team and a better player going forward.”

The Islanders relied on Tavares so heavily because the supporting cast continued to show little support. Even as coach Jack Capuano loaded up his top line, putting longtime friends and teammates Frans Nielsen and Kyle Okposo on either side of Tavares, they couldn’t produce any sustained pressure. The Lightning shut them down with superlative defenseman Victor Hedman — who also scored twice — and kept it clear for goalie Ben Bishop to stop all 28 shots he faced, notching the fifth postseason shutout of his career and sending the Lightning to their second straight conference final against the winner of the Capitals-Penguins series.

Yet when Capuano was asked if this group of players has enough to take the next step, or if big moves are needed, the coach still was too close to the loss to make a lucid evaluation.

“It’s a tough question for me to answer, because it’s an emotional time when you just lose,” Capuano said. “Those are meetings that we have with coaches and management, moving forward, you’re going to have to decide.”

So who is going to be around to learn from this experience is in question. The Isles knew they played well in Games 2, 3, 4 of this series, and lost all three — the third and fourth in overtime at their new digs at Barclays Center. Yet with their season on the line in Game 5, they came out with a dud of an effort, watching as Hedman scored his first at 13:40, and Brian Boyle got his third of the postseason to open a 2-0 lead before the opening 20 minutes ended.

“You can only defend as hard as you can defend,” Capuano said. “You’re gong to give up one or two, but you have to find a way in this league to score two or three a night if you’re going to win.”

They couldn’t score any, and Hedman added another on a second-period power play, and Nikita Kucherov scored his league-leading ninth of the postseason on a breakaway 4:40 into the third to seal it. The folk-hero status of regular backup goalie Thomas Greiss already had come to a screeching halt, the narrative now relegated only to that first-round series, as chinks in his armor were apparent throughout against the shifty and talented Lightning.

Greiss couldn’t save the day, and neither could Tavares or anyone else. So now it’s on to this summer of change, and what type of team comes out the other end is totally unknown.

“Hopefully we have the core of our team intact,” Tavares said,” and we’re able to find a way to overcome this and learn from this.”